1. Field of the Invention
The present invention relates to a technology for collecting various pieces of information and instructing operations by communicating with an agent installed in an information processing apparatus via a network and for updating software in the information processing apparatus, with a capability of automatically updating the software in the information processing apparatus employed in a complicated operation mode.
2. Description of the Related Art
Recently, information processing systems require a multifunction, and accordingly, some sort of problem can often lurk in the information processing system. If any problem is found in the information processing system, a remedy for the problem is generally provided in the form of a patch. The patch is a program or data that improves a problem in an information processing system, or a combination thereof.
When a patch is applied to an information processing system, it is required to follow a premised procedure, and another problem can be caused by following a wrong procedure. For example, when the patch is applied, it is sometimes required to stop a certain service in the information processing system or to apply another patch in advance.
For this reason, if there are many information processing systems and the patch needs to be applied to them, a heavy burden is put on an operator, and an erroneous operation is likely to cause a secondary failure. Therefore, inventions that make a patch-applying work more efficient and automatic have been made and disclosed (see, for example, Japanese Patent Laid-open No. 2003-296132 and Japanese Patent Laid-open No. 2003-108255).
However, as the operation mode of the information processing systems become more complicated, the patch-applying work cannot be supported enough by the conventional inventions.
For example, in a system that is required to have high throughput and high usability, servers are often operated in parallel using a load balancer. This operates a system in a mode where a plurality of servers installed with an identical application is arranged, the load balancer receives all requests from clients, and it assigns the process into any one of the servers.
By taking such operation mode, a plurality of servers can be operated as a single information processing apparatus by appearance, and increased number of the servers can improve the processing performance. Moreover, the number of the servers can be dynamically changed for the operation depending on the load status and occurrence of failures, whereby achieving high availability.
The mode using the load balancer is also advantageous in the patch-applying work. When a patch is applied, in many cases, it is necessary to stop the service of the server. In the mode using the load balancer, by performing a procedure with respect to each server, the procedure including disconnecting the server fro the load balancer to stop the service and connecting the server to the load balancer again after the patch is applied, the patch can be applied to all the servers without stopping providing the service.
The method of applying the patch to each server after being disconnected from the load balancer is referred to as a rolling application. The rolling application includes a great advantage of being able to apply the patch while the information system is in operation as described above; however, it also includes a disadvantage that erroneous operation can occur because configuration of the load balancer and the like needs to be changed and the procedure is very complicated. The inventions disclosed in Japanese Patent Laid-open No. 2003-296132 and Japanese Patent Laid-open No. 2003-108255 improve only the application of the patch, and they do not improve most part of the rolling application procedure.
The target system of the rolling application is, as described above, a system that operates servers in parallel, which is often a large-scale system. Therefore, if an erroneous operation occurs in the rolling application of the patch, an effect thereof is very likely to be very profound, and it is very important to prevent occurrence of the erroneous operation.